scholarly journals Optimal resource allocation in networked control systems using viterbi algorithm

2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Gökhan Çetin ◽  
M. Sami Fadali
Keyword(s):  
Bandwidth Allocation ◽  
Viterbi Algorithm ◽  
Networked Control Systems ◽  
Sampling Period ◽  
Networked Control System ◽  
Networked Control ◽  
Network Bandwidth ◽  
Window Width ◽  
Optimal Bandwidth Allocation ◽  
Network States

This paper presents an optimal bandwidth allocation method for a networked control system (NCS) which includes time-driven sensor, event-driven controller and random channels. A hidden markov model (HMM) with a discretized state space is formulated for the random traffic to predict the network states using a suitable data window. Network bandwidth is allocated based on the predicted traffic state subject to bounds on the deterministic traffic that guarantee acceptable NCS performance and do not exceed hardware limitations. Bandwidth allocation uses  minimization of unmet bandwidth demand. A stability condition is derived for a variable but bounded sampling period interval. Computer simulation results show the effect of varying the number of discrete states for the HMM and the window width on bandwidth allocation. The results compare favorably with a published approach based on fuzzy logic.

scholarly journals Dynamic Intelligent Feedback Scheduling in Networked Control Systems

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Hui-ying Chen ◽  
Zu-xin Li ◽  
Pei-liang Wang
Keyword(s):  
Networked Control Systems ◽  
Dynamic Performance ◽  
Networked Control System ◽  
Networked Control ◽  
Performance Indices ◽  
Available Bandwidth ◽  
Control Loops ◽  
Limited Bandwidth ◽  
Network Bandwidth ◽  
Feedback Scheduling

For the networked control system with limited bandwidth and flexible workload, a dynamic intelligent feedback scheduling strategy is proposed. Firstly, a monitor is used to acquire the current available network bandwidth. Then, the new available bandwidth in the next interval is predicted by using LS_SVM approach. At the same time, the dynamic performance indices of all control loops are obtained with a two-dimensional fuzzy logic modulator. Finally, the predicted network bandwidth is dynamically allocated by the bandwidth manager and the priority allocator in terms of the loops' dynamic performance indices. Simulation results show that the sampling periods and priorities of control loops are adjusted timely according to the network workload condition and the dynamic performance of control loops, which make the system running in the optimal state all the time.

scholarly journals Design of Multi-Rate Multi-Zone Wireless Fuzzy Temperature Control System for Greenhouse Application

2020 ◽  
Vol 26 (7) ◽  
pp. 97-114
Author(s):  
Qays Jebur Sabr
Keyword(s):  
Control System ◽  
Fuzzy Controller ◽  
Networked Control Systems ◽  
Sampling Rate ◽  
Sampling Period ◽  
Networked Control System ◽  
Networked Control ◽  
Temperature Control System ◽  
Temperature Controller ◽  
Input Gain

sensor sampling rate (SSR) may be an effective and crucial field in networked control systems.  Changing sensor sampling period after designing the networked control system is a critical matter for the stability of the system. In this article, a wireless networked control system with multi-rate sensor sampling is proposed to control the temperature of a multi-zone greenhouse. Here, a behavior based Mamdany fuzzy system is used in three approaches, first is to design the fuzzy temperature controller, second is to design a fuzzy gain selector and third is to design a fuzzy error handler. The main approach of the control system design is to control the input gain of the fuzzy temperature controller depending on the current zone and current sensor rate for each zone. Due to the low input gain of the fuzzy controller, the steady state output error of the greenhouse temperature is in the range (0.55 – 11.22) % when the system using five sensors of different sampling rates and in the range (2.43 - 16.74) % when the system using five sensors with the same sampling rates. Next, after designing the fuzzy error handler, this error doesn’t exceed 1.6%, but in most cases it is less than 0.15%.The work is Simulink designed and implemented using Matlab R2012b. The Zigbee wireless network is proposed for the system, it is implemented in Matlab using True time 2.0 library.

Deadband feedback-based scheduling approach for networked control system with variable sampling period

2021 ◽  
pp. 014233122098142
Author(s):  
Zhongda Tian
Keyword(s):  
Control System ◽  
Sampling Period ◽  
Networked Control System ◽  
Networked Control ◽  
Control Performance ◽  
Control Loops ◽  
Network Bandwidth ◽  
Network Utilization ◽  
Variable Sampling ◽  
Overall Performance

Reasonable information scheduling strategies in the networked control system (NCS) can improve the quality of service of the network, reduce the conflict of information transmission in the network, and improve the overall performance of the NCS. In order to improve the performance of the NCS, a deadband feedback-based scheduling approach for the NCS with a variable sampling period is proposed. For the NCS with multi control loops, considering the limitation of network bandwidth resources, the dynamic real-time adjustment of a multi-loop sampling period is achieved through network utilization prediction, network bandwidth configuration and sampling period calculation. Furthermore, deadband feedback scheduling is combined with a variable sampling period algorithm. Deadband is set in the sensor and controller nodes to effectively adjust the information flow of the forward channel and the feedback channel. The proposed scheduling approach can reduce the impact of network conflict and network delay on system stability, make the network resources allocated reasonably, save network data traffic, and improve the overall performance of the NCS. A NCS with five control loops is used as the simulation object and carried out by True Time toolbox. The simulation results show that the proposed scheduling approach can improve output control performance of the system, reduce integral absolute error value of the control loops, and improve network utilization. The overall control performance of the system is improved.

Modeling and Stability Analysis of Multi-Rate Networked Control Systems with Multiple Control Loops

2010 ◽  
Vol 139-141 ◽  
pp. 1827-1833 ◽  
Author(s):  
Dian Ting Liu ◽  
De Jian Zhou ◽  
Yao Ming Liu
Keyword(s):  
Control System ◽  
Networked Control Systems ◽  
Sampling Period ◽  
Networked Control System ◽  
Network Control ◽  
Networked Control ◽  
Control Loop ◽  
Multiple Control ◽  
Control Loops ◽  
Analysis And Design

A kind of multi-input and multi-output network control system with multiple independent control loops is examined in this paper. The controller of each control loop is connected with the sensor and actuator by a network and each control loop has a different sampling period. The whole mathematical model of this kind of networked control system is set up when the maximum network-induced delay is smaller than one sampling period. And the sufficient condition subject to the asymptotic stability of this kind of networked control system is derived based on the theorem for estimation of feature value deduced from perturbation theory. The research results of this paper have significance in the analysis and design of this kind of networked control system or a similar networked control system.

Optimal Bandwidth Allocation and QoS-Adaptive Control Co-Design for Networked Control Systems

2007 ◽  
Author(s):  
Kun Ji ◽  
Won-Jong Kim
Keyword(s):  
Adaptive Control ◽  
Control Systems ◽  
Bandwidth Allocation ◽  
Design Methodology ◽  
Networked Control Systems ◽  
Networked Control ◽  
Control Performance ◽  
Control Loop ◽  
Network Bandwidth

In this paper, we present a co-design methodology of dynamic optimal network-bandwidth allocation (ONBA) and adaptive control for networked control systems (NCSs) to optimize overall control performance and reduce total network-bandwidth usage. The proposed dynamic co-design strategy integrates adaptive feedback control with real-time scheduling. As part of this co-design methodology, a “closed-loop” ONBA algorithm for NCSs with communication constraints is presented. Network-bandwidth is dynamically assigned to each control loop according to the quality of performance (QoP) information of each control loop. As another part of the co-design methodology, a network quality of service (QoS)-adaptive control design approach is also presented. The idea is based on calculating new control values with reference to the network QoS parameters such as time delays and packet losses measured online. Simulation results show that this co-design approach significantly improves overall control performance and utilizes less bandwidth compared to static strategies.

Perturbations in Networked Control Systems

2001 ◽  
Author(s):  
Octavian Beldiman ◽  
Linda G. Bushnell ◽  
Gregory C. Walsh ◽  
Hua O. Wang ◽  
Yiguang Hong
Keyword(s):  
Control System ◽  
Control Systems ◽  
Networked Control Systems ◽  
Networked Control System ◽  
Networked Control ◽  
Asymptotically Stable ◽  
Networked System ◽  
External Perturbations ◽  
Exponentially Stable

Abstract In this paper we study the effect of external perturbations on a networked control system. We start by assuming that the non-networked system without perturbation is exponentially stable. Then, for fast enough networks we show that if the perturbation is bounded the networked system is ultimately bounded and if the perturbation is vanishing then the networked system is asymptotically stable. We conclude the paper with simulations verifying the results.

Output Feedback Stabilization of Networked Control Systems with Time-Varying Delay

2013 ◽  
Vol 718-720 ◽  
pp. 1836-1841
Author(s):  
Xue Feng Zhang ◽  
Yan Xia Shen ◽  
Hua Ping Zhang
Keyword(s):  
Control Systems ◽  
Output Feedback ◽  
Networked Control Systems ◽  
Networked Control System ◽  
Feedback Stabilization ◽  
Networked Control ◽  
Time Varying ◽  
Time Varying Delay ◽  
Output Feedback Stabilization ◽  
Varying Delay

The problem of output feedback stabilization for networked control system with time-varying delay is discussed. By constructing a novel LyapunovKrasovskii functional,the output feedback controller is obtained in terms of LMIs. The dynamics information of the time-varying delay is taken into account in the structured controller, and the obtained result is less conservative. A numerical example is given to illustrate the effectiveness of the presented method.

scholarly journals Active-Varying Sampling-Based Fault Detection Filter Design for Networked Control Systems

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yu-Long Wang ◽  
Tian-Bao Wang ◽  
Wei-Wei Che
Keyword(s):  
Fault Detection ◽  
Control Systems ◽  
Networked Control Systems ◽  
Filter Design ◽  
Sampling Period ◽  
Networked Control ◽  
Packet Dropouts ◽  
Fault Detection Filter ◽  
Simulation Results ◽  
Detection Filter

This paper is concerned with fault detection filter design for continuous-time networked control systems considering packet dropouts and network-induced delays. The active-varying sampling period method is introduced to establish a new discretized model for the considered networked control systems. The mutually exclusive distribution characteristic of packet dropouts and network-induced delays is made full use of to derive less conservative fault detection filter design criteria. Compared with the fault detection filter design adopting a constant sampling period, the proposed active-varying sampling-based fault detection filter design can improve the sensitivity of the residual signal to faults and shorten the needed time for fault detection. The simulation results illustrate the merits and effectiveness of the proposed fault detection filter design.

scholarly journals Comprehensive Control of Networked Control Systems with Multistep Delay

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Jie Jiang ◽  
Changlin Ma
Keyword(s):  
Time Delay ◽  
Control Systems ◽  
Networked Control Systems ◽  
Sampling Period ◽  
Networked Control ◽  
Control Methods ◽  
Delay Compensation ◽  
Linear Quadratic ◽  
Long Time ◽  
Time Delay Compensation

In networked control systems with multi-step delay, long time-delay causes vacant sampling and controller design difficulty. In order to solve the above problems, comprehensive control methods are proposed in this paper. Time-delay compensation control and linear-quadratic-Guassian (LQG) optimal control are adopted and the systems switch different controllers between two different states. LQG optimal controller is used with probability1-αin normal state, which is shown to render the systems mean square exponentially stable. Time-delay compensation controller is used with probabilityαin abnormal state to compensate vacant sampling and long time-delay. In addition, a buffer window is established at the actuator of the systems to store some history control inputs which are used to estimate the control state of present sampling period under the vacant sampling cases. The comprehensive control methods simplify control design which is easier to be implemented in engineering. The performance of the systems is also improved. Simulation results verify the validity of the proposed theory.

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